Question

Induced dipole moment depends upon the _____________ of the permanent dipole moment and the _________________ of electrically neutral molecules.
(a) dipole moment, polarizability
(b) polarizability, dipole moment
(c) polarizability, polarizability
(d) None of these

Answer 1

Hint: Induced dipole moment is the dipole moment which has occurred due to induction of charge by the action of the other molecule. Polarizability is the ratio of induced dipole moment, and the field which is applied to it.

Complete step by step answer:
(1) Dipole means two poles. Pole is a term used to specify charges. Dipole moment is the result of separation of charges. Whenever, in a molecule of two atoms, one atom is more electronegative than the other. Electronegativity is the tendency to attract a shared pair of electrons toward itself in a covalent bond. Due to the result of this electronegativity difference, electrons go towards the more electronegative atom which creates a negative pole on the more electronegative atom, and positive pole on the other atom.

(2) When a molecule with a dipole moment comes close to an electrically neutral molecule then the positive charged cloud of the molecule which has dipole moment attracts the electron cloud of the neutral molecule. This induces a dipole in the electrically neutral molecule also. This dipole is called induced dipole moment.

(3) If a molecule has induced dipole moment of ${\text{p}}$, and field of strength ${\text{E}}$ is applied to it, the, the polarizability will be the ratio of ${\text{p and E}}$. Polarizability is denoted by $\alpha $, and $\alpha = \dfrac{{\text{p}}}{{\text{E}}}$.
Whether a dipole moment can be induced in a molecule or not is decided by polarizability of the electrically neutral molecule.

So, the correct answer is Option A.

Note:
Dipole-dipole interaction can be understood by taking the example of Hydrogen Chloride, ${\text{HCl}}$. Hydrogen end is relatively positive which is attracted by the Chlorine atom end which is relatively negative in charge. This makes ${\text{HCl}}$ a dipole.